Question

What is the best practice to run two or more services consistently?

For example:
REST service retrive some data and if there is some new stuff download service should be ran?

I’m sending broadcast to receiver after first is finished, and receiver grabs data from intent and send it to second service.

Answer 1

You could as well send an Intent from the RestService directly to the DownloadService without putting the BroadcastReceiver between the two of them.

I think IntentService will be a better aproach for your DownloadService.

IntentService is a base class for Services that handle asynchronous requests (expressed as Intents) on demand. Clients send requests through startService(Intent) calls; the service is started as needed, handles each Intent in turn using a worker thread, and stops itself when it runs out of work.

This "work queue processor" pattern is commonly used to offload tasks from an application’s main thread. The IntentService class exists to simplify this pattern and take care of the mechanics. To use it, extend IntentService and implement onHandleIntent(Intent). IntentService will receive the Intents, launch a worker thread, and stop the service as appropriate.

All requests are handled on a single worker thread — they may take as long as necessary (and will not block the application’s main loop), but only one request will be processed at a time.

EDIT: forgot to mention that since API Level 9 Android has a DownloadManager class that handles your downloads, retries them after failures, connectivity changes, etc.